This invention relates to a device for passing weft yarns to at least one weft insertion means on a weaving machine, which can be operated in order either to bring a weft within the weft feed area of the weft insertion means so that a weft can be inserted, or to hold it out of this feed area to effectuate a weft cancellation.
This device also relates to a weaving machine provided with such a offering device for wefts.
Known weaving machines comprise a mechanism for inserting wefts between warp yarns. Such a mechanism comprises one or more weft insertion means, such as for example rapiers, which can be operated in order in the course of successive weft insertion cycles to bring a respective weft into a shed formed between warp yarns.
In order to be able to weave certain weave constructions or to be able to weave in an efficient manner it is necessary to prevent the insertion of one of more wefts in the course of certain insertion cycles. By means of the above described device this can be effected automatically. The prevention of the insertion of a weft by a weft insertion means is generally referred to by the term "weft cancellation".
Such offering devices for wefts with which weft cancellations can be effected automatically are generally known.
The known devices comprise weft cutters which are provided in order after each weft insertion to cut off the piece of weft yarn, inserted in the fabric, from the weft yarn fed from the supply package, and in order, after cutting off the piece of weft, to clamp the free extremity of the fed weft. These weft cutters are connected to the weaving batten and therefore move back and forth with every beating-up. The clamped weft is brought below the movement path of a rapier in the course of the return movement of the weaving batten. These devices furthermore also comprise a swivelling arm with a guiding eye for the weft. The swivelling arm is rotatably connected to the frame of the weaving machine and can be operated in order whether or not to bring the weft extending through the guiding eye above the movement path of the rapier.
If a weft has to be inserted the weft cutters are operated in order to cut through and clamp the weft. The clamping means move with the weaving batten and bring the weft under the rapier movement path. The swivelling arm is at that moment rotated to a position in which the guiding eye brings the weft above the movement path of the rapier, so that the part of the weft extending between the clamping means and the guiding eye is within the feed area of the rapier.
If on the other hand a weft cancellation has to be effected the weft cutters are not operated in order to cut through the weft. The weft therefore remains connected to the fell of the fabric and is also not clamped by the clamping means. Because of this the weft is also not carried to below the rapier movement path, with the beating-up movement of the batten. The swivelling arm is also not operated to bring the weft to above this movement path, so that the weft remains outside the feed area of the rapier.
A disadvantage of these known devices is that the swivelling levers and their operation are rather complex and expensive.